The energy savings from cool, reflective, roofs have long made them the go-to roof choice in warmer and temperate climates here in the United States. Both ASHRAE and the International Energy Conservation Code have included roof surface reflectivity requirements for a number of years. About half of all new flat roofs installed in the country are highly reflective and in some product categories white options outsell dark ones by a substantial margin. It is hard to argue with the notion that, where it is warm, the roofs should be white. While the building-level impacts of cool roofs in cool climates has been covered in the past, very little has been written about the broader economic benefits of cooler buildings and cities. When we include the economic impacts of factors like improved health, air quality, and energy savings, the case for cool roofs in cool climates looks even better.

The Benefits of Cool Roofs Go Way Beyond the Building

The building-level impacts of cool roofs are a central part of the discussion about whether they should be used in cold climates. However, it is also important to recognize the substantial co-benefits that come from installing cool roofs in terms of healthier and more comfortable people, improved productivity, better air quality, and increased economic prosperity. While the economic benefits of cool roofs are substantial, they may not always be fully included in a building owner’s roof buying decision.

How much cooler could our cities become if we added more reflective roofs? In a comprehensive review on this topic, Santamouris 2012 found that when a global increase of the city’s albedo is considered, the expected mean decrease of the average ambient temperature is close to 0.5°F (0.3°C) per 0.1 increase in reflectivity, while the corresponding average decrease of the peak ambient temperature is close to 1.6°F (0.9°C). The cooling impact of reflective roofs in certain neighborhoods could be significantly better, though. A study of Chicago by Notre Dame University found that installing reflective roofs cooled city surfaces by around 3.5 to 5.5°F (2-3°C), but surfaces in the downtown core cooled by 12.5 to 14.5°F (7-8°C).

Cool Cities Are Energy Savers

We have started to better understand and quantify the impact in cities that are able to get a degree or two of cooling. The most obvious benefit is that cooler cities demand less energy on hot days. The graph in Figure 1 plots electricity demand in

Washington, D.C., against the maximum temperature every day for 5 years (2010–2015). The graph’s shape looks very similar to plots from other cities with high penetrations of air conditioning units. Demand for electricity climbs rapidly above about 80°F. When the maximum temperature is 90°F, the city requires 21 percent more electricity, on average, than on 80°F days. At 95°F, demand has spiked by nearly 40 percent over the 80°F baseline. Charges for peak electricity demand are a major expense for commercial and industrial building operators and, in seventeen states, for homeowners as well. Further, peaking demand is often met by less efficient, more expensive, and dirtier power plants that worsen air quality. At worst, peak demand can cause productivity-killing service interruptions or brownouts.

Cooler Cities Are Healthier Places

Heat is a potent but silent killer. On average, heat kills more people than any other natural disaster, and heat-related deaths tend to be underreported. In 2015, Scientific American reported that 9 out of the 10 deadliest heat events in history have occurred since 2000 and have led to nearly 130,000 deaths. Cities on dangerously hot days experience 7 percent to 14 percent spikes in mortality from all causes.

Heat stress and stroke are only the tip of the pyramid of heat health impacts. Heat puts significant additional stress on people already suffering from diseases of the heart, lungs, kidneys, and/or diabetes. A recent study finds that every 1.5°F increase in temperatures will kill 5.4 more people per 100,000 people every year.

Installing cool roofs or vegetation can lead to a meaningful reduction in heat deaths by making the daytime weather conditions more tolerable. There are a number of studies estimating the impact of increasing urban reflectivity and vegetative cover on weather conditions. Kalkstein 2012 and Vanos 2013 looked at past heat waves in 4 U.S. cities and modeled the impact of increasing reflectivity by 0.1 (the estimated equivalent of switching about 25 percent of roofs from dark to light colors) and vegetative cover by 10 percent. Though the sample sizes are too small to draw sweeping conclusions, the studies found that cities making these modest changes could shift weather into less dangerous conditions and reduce mortality by 6 percent to 7 percent.

Cooler Cities Are Engines of Economic Growth

The health, air quality, and energy benefits of modest increases in urban roof reflectivity could generate billions of dollars of

(Figure 3) An infrared scan of Sacramento, Calif., shows the range of surface temperatures in the area. Source: Lawrence Berkeley National Laboratories.

economic prosperity for our cities. A study of 1,700 cities published in the Journal Nature Climate Change found that changing only 20 percent of a city’s roofs and half of its pavement to cool options could save up to 12 times what they cost to install and maintain, and reduce air temperatures by about 1.5°F (0.8°C). For the average city, such an outcome would generate over a $1 billion in net economic benefits. Best of all, adding cool roofs to between 20 and 30 percent of urban buildings is a very realistic target if existing urban heat island mitigation policy best practices are adopted.

Cool Roof Performance in Cold Climates: In Brief

As positive as cool roofs are for cities in cool climates, they first have to be a high-performing choice for the building itself. What do we know about net energy savings in cool climates with higher heating load? This question was the subject of “There is Evidence Cool Roofs Provide Benefits to Buildings in Climate Zones 4-8” in the November/December 2016 issue of Roofing that summarized the newest science and field studies that show that reflective roofs provide net energy benefits and favorable heat flux impacts on roofs in cold climates. In short, the newest research from Columbia, Princeton and others demonstrates that the size of the “winter heating penalty” is significantly less than many had thought and shows net reductions in annual energy use when cool roofs are used, even with roof insulation levels as high as R48.

Real Cool Roofs in Cold Climates: The Target Survey

It is not just the science that supports the use of reflective roofs in cold climates. The strong and steady growth of cool roofing in northern markets over the last decade or two is also a good indication that reflective roofs are a high-performance option in those areas. For almost 20 years, Target Corporation has installed reflective PVC membranes on nearly all of its stores in the

Studies estimate that modest increases in urban roof reflectivity could generate billions of dollars of economic prosperity for cities. Pictured here is the roof on the Cricket Club in Toronto. Photo: Steve Pataki

United States and Canada. The membranes are usually installed over a steel deck with no vapor retarder. Target and manufacturer Sika Corporation undertook a field study of 26 roofs on randomly chosen stores located in ASHRAE Climate Zones 4-6 including Connecticut, Illinois, Massachusetts, Michigan, Minnesota, New York, Washington, and Wisconsin. The roofs were 10-14 years old at the time of the survey. None of the 51 total roof sample cuts were made across these roofs showed signs of condensation damage. A more detailed accounting of the study by representatives of Target Corporation and Sika Sarnafil published in Building Enclosure includes this important paragraph from authors Michael Fenner, Michael DiPietro and Stanley Graveline:

“Specific operational and other costs are confidential information and cannot be disclosed. However, it can be stated unequivocally that although the magnitude varies, Target has experienced net energy savings from the use of cool roofs in all but the most extreme climates. Although the savings in northern states are clearly less than those achieved in southern locations, experience over approximately two decades has validated the ongoing use of cool roofs across the entire real estate portfolio. Even in climates with lengthy heating seasons, overall cooling costs exceed heating costs in Target’s facilities.”

It is increasingly clear that installing cool roofs is the definition of “doing well by doing good.” Even in cold areas, a properly built roof system with a reflective surface is a high-performance option that delivers value for building owners while making hugely positive contributions to the neighborhoods and cities they occupy.

NTEC Systems applied a high-solids silicone coating. The system was chosen because it would extend the life of the existing roof and cut utility costs for the building. The system was approved for a 20-year warranty.Photos: NTEC Systems

Thomas Portaro is the owner of NTEC Systems, a company headquartered in Alpharetta, Ga., that specializes in roof restoration projects. Portaro owns the company, but on a recent project on the campus of Georgia Tech, it was definitely the college students who were in charge.

Portaro was contacted by students who were researching different roof systems as part of a class project. Members of the class had been tasked to come up with ways to reduce carbon dioxide emissions on the school’s Atlanta campus.

Students were exploring all sorts of environmentally friendly building systems, including LED lighting and HVAC equipment. One group of students explored various building envelope modifications, eventually narrowing their focus to the roof system.

“This particular group of students showed the school and their professors how they were going to reduce carbon emissions and the energy footprint of the O. Lamar Allen Sustainable Education Building by doing a roof restoration,” Portaro said.

Photos: NTEC Systems

Portaro, a Georgia Tech graduate, was contacted by the group to provide some insights on the potential benefits of coatings. “I was asked to come down to the campus and give a brief lecture on the values of roof restorations, the types of coatings I was familiar with, how they were applied, and how they could restore this particular roof.

The building was built in 1998, and its roof was the original modified bitumen system. When students learned how a cool roof system would extend the life of the roof and save on utility costs for the building, they not only presented their findings to their professors but officials at the university. The school ultimately decided to fund the project.

NTEC Systems completed the installation of a high-solids silicone roof coating manufactured by GE. “The students pioneered all of this,” Portaro says. “This is an amazing group of kids. To be invited back to my alma mater and to execute this project really hit a chord with me. The project really worked out well, and it was really cool because I got a check from Georgia Tech. Think about all of the money I’ve paid them over the years. It was nice to get a little bit of that money back.”

Practical Application

One key concern for the university was achieving a 20-year warranty, so the first step was to ensure that the existing roof was compatible with the system. “One of the big value adds of GE Performance Coatings is that their tech side is very strong,” Portaro notes. “GE has great specifications, and they make it pretty simple for me as an engineer to go up and evaluate a roof and make sure it meets certain criteria. You have to evaluate each roof to ensure it meets the criteria for a restoration.”

“A great phrase—and I forget who coined it—is, ‘We do roof restorations, not roof resurrections,’” Portaro continues. “The existing roof has to be in a restorable condition.”

Georgia Tech funded a roof restoration for the O. Lamar Allen Sustainable Education Building after a student project detailed the energy-saving benefits of a cool roof coating.Photos: NTEC Systems

Infrared analysis was conducted to ensure the roof system was dry. Some minor repairs were needed, but overall the modified roof was in good shape. It was cleaned with pressure washer and primed with an asphalt bleed-blocker from GE Performance Coatings. NTEC crews then spray-applied two coats of GE Enduris 3502 high-solids silicone roof coating to a minimum thickness of 40 mils when dry. The system forms a monolithic coating that is self-flashing. “We detailed it all out, the inspectors inspected it, and at the end of the day it was all done, the 20-year warranty was in place, and everyone was happy,” Portaro says.

He points out that the GE silicone coatings rarely require a primer. “This is the only type of roof that requires a primer, and the only reason it does is that asphalts tend to bleed through silicones and can tobacco-stain them,” he notes. “It’s aesthetics—that’s it. The GE system is one of our ‘tried and trues’ in part because for 99 percent of the roofs we do, it’s a primerless system. So, we save that step, which saves us time and ultimately saves the owner money.”

NTEC Systems excels at large, high-volume jobs, and the company is always looking for tools to make it more productive. “We are highly automated here,” Portaro says. “That’s our strength. It’s what we do. We have the ability to do a ton of square footage in a short period of time because we have the latest and greatest machinery. We’ve actually created our own method of going from ground to roof and getting coatings spray applied.”

The company has modified some industrial machinery to move large volumes of high-solids silicone under control, according to Portaro. “Now, it’s not robotics,” he explains. “It still takes artistry. It still takes an expert pulling the trigger. We have guys that are very talented, and now the machinery is keeping up. We can do four or five times as much work in a day as we used to do just a few years ago. Our production levels have blown up.”

A Learning Experience

Photos: NTEC Systems

One of the challenges on this project was taking the time to use the application as a teaching tool. “The students were there the entire time,” Portaro remembers. “We were surrounded by some of the smartest people in the world. I’ve never had so many managers on a project in my life. These students brought a passion to the building industry like you’ve never seen before. They believe they are going to change the world, and they probably will.”

Portaro also shared his passion for environmentally friendly roof systems. The students apparently took that message to heart. “These kids are something special,” he says. “They went to Washington, D.C., to present this project to the Congress of the United States. These kids weren’t happy with just affecting one building on the campus of Georgia Tech. They wanted to share the story. This project got national recognition. I was really proud of these kids, who I met for the first time on this project. My hat’s off to them.”

Portaro has installed a lot of cool roofs, but the Georgia Tech project was special. “This was certainly the coolest project I’ve ever done,” he says.

Kemper System America Inc. now offers two cost-effective ‘cool roof’ solutions for prolonging the life of metal, BUR, modified bitumen and aged single-ply roof systems.

Roof Guardian RG-170 is an elastomer-based coating system ideal for extending the life of many types of roofing assemblies. Formulated using a 100 percent acrylic polymer base for enhanced adhesion and durability, the coating features a high Solar Reflectance Index (SRI) rating of 109 and is Class A fire rated. Roof Guardian RG-180 is a fiber-reinforced elastomeric coating with an acrylic polymer base, ideal for metal, concrete, single ply, modified bitumen, and granular cap sheets. It offers an SRI rating of 108.

“Kemper System has been at the vanguard of liquid-applied roof waterproofing solutions for decades. These two new white Roof Guardian coating systems offer a quick and cost-effective approach for transforming many kinds of existing low-slope roofs into a cool roof that can help building owners cut cooling costs,” says Jim Arnold, Director of Product Development for Kemper System.

Part of the company’s Roof Guardian Technologies line, the roof coatings can be quickly applied with a commercial-grade sprayer or roller. The highly reflective bright white finish lowers the surface temperature of the substrate to reduce thermal transfer into the structure. This high solar reflectance helps lower indoor temperatures to reduce building cooling requirements.

“For more than 60 years, Kemper System has been a global industry leader in cold liquid- applied, reinforced roofing and waterproofing, having invented the technology and holding the first patents,” says Arnold. “Today the company offers a full range of building envelope solutions to protect against weather, preserve the integrity of surfaces, and enhance the comfort and value of buildings.”

The reflective granulated cap sheet may be used as a cap or flashing sheet in built-up roof systems.

Johns Manville has introduced a highly reflective granulated cap sheet called GlasKap CR G, which may be used as a cap or flashing sheet in built-up roof systems. The CR G membranes are surfaced with white reflective minerals and can be installed using standard granulated cap sheet installation methods. GlasKap CR G joins the larger offering of JM cool roof membrane solutions. These products are approved by FM Global and UL. They are also listed with CRRC and meet current Title 24 requirements. GlasKap CR G provides an additional option for customers who want a reflective cap sheet as part of a reliable BUR system.

Kemper System protects surfaces across the globe. Solutions to be featured at IRE include:

Two fully reinforced membrane systems that can transform roof decks into reflective cool roofs, or provide monolithic protection for green roofs, blue roofs, and a range of other projects.

Two new coatings systems for protecting surfaces prone to heavy wear such as parking garages, balconies and walkways.

Waterproofing Membrane Systems

The two reinforced waterproofing membrane systems are cold liquid-applied and ideal for cool roof applications:

Kemperol AC Speed FR system is a Polymethyl Methacrylate (PMMA)

Kemperol Reflect 2K FR is a low-VOC system

Both are fire rated for Class A assemblies and exceed LEED solar reflective requirements with SRI ratings of 108 and 110, respectively.

Durable Wear Coatings

For protecting parking garages, pedestrian decks, and loading docks, the COLEAN Parking System can withstand deterioration caused by natural elements and vehicular traffic. In addition, the COLEAN Balcony System, which is designed to expand and contract with normal structural movements, protects balconies, terraces, walkways, patios, sun decks, and machine rooms from freeze/thaw damage and chemical exposure.

Kemper System America also offers a way to prolong the life of existing roofs with elastomer-based coating systems, one of four technologies added through the acquisition of STS Coatings Inc. in December.

“Our building envelope solutions go beyond roof waterproofing to make the building specifier’s job easier. These solutions create opportunities for contractors and value for building owners,” says Richard Doornink, president and managing director of Kemper System America Inc.

For over 60 years, Kemper System has led in cold-liquid applied, reinforced roofing and waterproofing, having invented the technology and holding the first patents. Today the company offers a range of building envelope solutions to protect against weather, preserve the integrity of surfaces, and enhance the comfort and value of public buildings and commercial real estate.

Kemper System is celebrating 60 years of success and building on its strengths to address the entire Building Envelope.

“Kemper System was built on novel approaches to challenges, product quality and customer service, and those continue to be the bedrock of our relationships,” says Richard Doornink, president and managing director of Kemper System America Inc. “Our role is to help architects and other specifiers find the balance between often competing goals on projects across the Building Envelope. The right technology makes those choices easier,” he states.

Today, the company offers an expanded range of Building Envelope solutions to protect against weather, preserve the integrity of surfaces and enhance the comfort and value of public buildings and commercial real estate.

As part of the company’s expansion efforts, Kemper System America acquired STS Coatings Inc. in December along with four flagship brands, and is exploring additional technologies to build its portfolio, Doornink stated. In addition to the technologies from STS Coatings, this encompasses Kemperol reinforced membrane systems, and COLEAN durable coatings systems for protecting surfaces prone to heavy wear.

Technology Roots

Kemper System traces its roots to polymer chemist Heinz B. Kemper, Ph.D., who founded the original company in 1957 after developing a roofing system using a cold liquid-applied resin reinforced with polyester fleece. After conducting over 200 trials, in 1969 he patented Kemperol V210, a reinforced membrane system which proved to be effective, and could stand up to sun, rain, snow, ice and standing water longer term.

That led to further advances in cold, liquid-applied membranes including the company’s flagship solvent-free and odor-free Kemperol 2K PUR membrane system, launched in the U.S. in 1999, and more recently, Kemperol 022 reinforced waterproofing system for indoor tile, and fire-rated Cool Roof systems – the odor-free Kemperol Reflect 2K FR and fast-curing Kemperol AC Speed FR.

Today, Kemper System products protect surfaces under a range of climatic conditions spanning: new and existing roofs, white roofs, green roofs, blue roofs, interior and below-grade waterproofing, parking garages, balconies, terraces, plazas and historic restorations. In North America, Kemperol membrane systems protect projects including the Empire State Building in New York, CN Tower in Toronto and Marketplace Tower in Seattle.

Kemper System America Inc. is a wholly owned subsidiary of Kemper System GmbH & Co. (KG | Holländische Straße 32-36 | D-34246 Vellmar). Kemper System is part of the IBG Group of companies, a mid-sized industrial holding company with more than 50 sales and distribution sites, as well as production companies all over the world.

Boral Roofing LLC, a provider of sustainable clay and concrete roof tile systems, has announced that its Boral Cool Roof System will be featured on the 2017 New American Remodeled Home. Located in Lake Nona in South Orlando, the New American Remodeled Home is a joint collaboration of “Professional Builder” magazine, National Association of Home Builders (NAHB) and builder Phil Kean Design Group. The project exemplifies how an existing home may be improved in design, livability and energy efficiency and will showcase Boral Roofing’s Saxony 900 Slate concrete roof tile.

“One of the benefits of the Boral Cool Roof System is its energy efficiency performance,” says Rich Thomas, product manager for Boral Roofing. “While providing long-term energy savings to the building owner, our roof tile is also durable with curb appeal.”

The Boral Cool Roof System to be featured on the home includes a number of key components including the Saxony 900 Slate roof tile, elevated batten system, vented eave risers and ridge vent. The system’s elements work together to both protect the home from the elements and to conserve energy and prevent temperature fluctuations within the home. These energy efficient qualities reduce heating and cooling demands and provide energy bill savings for the lifetime of the roof.

Saxony 900 Slate is designed to complement both French and Tudor architectural styles and fully captures the appearance of natural slate. The roof tile requires minimal maintenance and is Class A Fire rated. The roof tile replaces the original tile roof put in place when the home was built in 1987. Premier Roofing completed the installation of the roof tile.

“The Boral Cool Roof System will assist in improving the overall performance of a building,” adds Thomas. “It will also help the building visionaries update this home to address the architectural design trends of the future.”

The Kemperol AC Speed FR system is a fast-curing, cold liquid-applied cool roof solution with a Solar Reflective Index rating of 108.

The Kemperol AC Speed FR system from Kemper System America Inc. is a fast-curing, cold liquid-applied cool roof solution with a Solar Reflective Index rating of 108. The system includes a two-part liquid-applied Polymethyl Methacrylate (PMMA) resin and a reinforcing layer; these components form a fully reinforced monolithic membrane. The resin cures in a matter of minutes, and the system does not require a topcoat, which reduces installation time and the cost of labor. In most cases, application can be completed in a day’s time. The fully reinforced membrane system can withstand battering from extreme sunlight, wind and precipitation. It fully adheres to substrates and is self-terminating and self-flashing.

Mule-Hide Products Co. has made available SA-APP KoolCap and SA-APP KoolCap FR modified bitumen roofing membranes, which adhere to a variety of roofing substrates. The products deliver the safety and ease of self-adhering application, long-term performance and durability, as well as the benefits of a cool roof. Complementing the membranes is the new SA-APP KoolCap Touch-Up Kit for treating lap areas, details and repairs. The granular-surfaced cap sheets are manufactured using a patented dual-compound technology in which a true APP polymer modified asphalt compound is applied to the top, weathering side and a proprietary adhesive formulation is applied to the bottom surface.

Rhino Linings released a complete cool roof system engineered to improve building energy efficiency while extending the service life of new and existing roofs.

Rhino Linings Corp., a manufacturer and distributor of spray-on protective linings, coatings and foam, released a complete cool roof system engineered to improve building energy efficiency while extending the service life of new and existing roofs.

The DuraTite spray polyurethane foam (SPF) roofing system holds a UL 790 Class A fire rating and is designed to provide a lightweight insulation system over various roof constructions and configurations. Unlike traditional roofing methods, DuraTite SPF roofing system offers a high R-value for superior thermal insulation, covers complex geometrical shapes and protrusions and applies directly to existing substrates in new and retrofit applications.

In addition to DuraTite SPF roofing system’s high-performance, it also offers significant life-cycle cost savings. An SPF roofing system is seamless and requires little-to-no maintenance. Roofing topcoats, like DuraTite acrylic, silicone, urethane and polyurea coatings may be reapplied numerous times, increasing the life of the roof.

The complete system combines spray foam with a full range of acrylic, silicone, urethane and polyurea coatings for a total roofing system that insulates, seals and protects. Products in this system include:

Silicone Coatings — DuraTite 1380 and DuraTite 1395 are high-solid, single-component, silicone coatings with low VOCs and excellent chemical and abrasion resistance. When applied, DuraTite 1380 and 1395 form a breathable membrane, making it an ideal choice for new and recoat applications over metals, single-ply membranes, masonry block, concrete and spray polyurethane foam roofing systems where moisture may be present.

DuraTite SPF roofing system guide specifications and five-, 10-, 15- and 20-year warranties are available for use on roof substrates, such as metal, built-up roof membrane, single ply, wood recoat and concrete.

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November/December 2018

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About Roofing

Roofing is a national publication that unravels, investigates and analyzes how to properly design, install and maintain a roof system. Through the voices of professionals in the field, Roofing’s editorial provides a unique perspective.